Narrative:

During taxi from ramp at A2, our departure runway was changed from runway 25R to runway 24L. As we taxied west on taxiway a, as directed by ground. The first officer was working new takeoff data for FMS input on our performance laptop while I taxied and monitored the radios. Passing taxiway G, we switched to tower, as directed, and was told to 'hold short of runway 25L at taxiway P.' I read back 'roger, air carrier X hold short of runway 25L at taxiway P.' as we passed taxiway A7 I heard several calls to an air carrier Y jet (by tower) to 'taxi into position and hold, traffic crossing downfield.' approaching taxiway north, my first officer said 'I'm putting the laptop away for now to listen for our clearance to cross.' after several more calls to air carrier Y and as we approached taxiway P, we both heard 'air carrier X clearance to cross runway 25L, hold short of runway 25R.' the first officer read back 'roger, air carrier X crossing runway 25L, hold short of runway 25R.' I then asked him as we turned on taxiway P to cross 'did you say air carrier Y crossing runway 25L?' he said 'no, I don't think so!' after crossing, we were told by ground to call the tower upon our arrival in oak. After arriving oak, we were informed that we crossed runway 25L without clearance. The results of the investigation are pending a review of the tapes. Contributing factors to this event are: congested radio traffic, poor visibility due to rain and darkness, and the first officer was on his third leg of IOE coming from so DC10. Supplemental information from acn 564933: received clearance to cross runway 25L, hold short of runway 25R. Read back the clearance and taxied.

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Original NASA ASRS Text

Title: AN MD11 CREW, TAXIING FOR TKOF AT LAX, TO THE CHAGRIN OF ATC, CROSSED RWY 25L AFTER HEARING WHAT THEY THOUGHT WAS A CLRNC TO DO SO.

Narrative: DURING TAXI FROM RAMP AT A2, OUR DEP RWY WAS CHANGED FROM RWY 25R TO RWY 24L. AS WE TAXIED W ON TXWY A, AS DIRECTED BY GND. THE FO WAS WORKING NEW TKOF DATA FOR FMS INPUT ON OUR PERFORMANCE LAPTOP WHILE I TAXIED AND MONITORED THE RADIOS. PASSING TXWY G, WE SWITCHED TO TWR, AS DIRECTED, AND WAS TOLD TO 'HOLD SHORT OF RWY 25L AT TXWY P.' I READ BACK 'ROGER, ACR X HOLD SHORT OF RWY 25L AT TXWY P.' AS WE PASSED TXWY A7 I HEARD SEVERAL CALLS TO AN ACR Y JET (BY TWR) TO 'TAXI INTO POS AND HOLD, TFC XING DOWNFIELD.' APCHING TXWY N, MY FO SAID 'I'M PUTTING THE LAPTOP AWAY FOR NOW TO LISTEN FOR OUR CLRNC TO CROSS.' AFTER SEVERAL MORE CALLS TO ACR Y AND AS WE APCHED TXWY P, WE BOTH HEARD 'ACR X CLRNC TO CROSS RWY 25L, HOLD SHORT OF RWY 25R.' THE FO READ BACK 'ROGER, ACR X XING RWY 25L, HOLD SHORT OF RWY 25R.' I THEN ASKED HIM AS WE TURNED ON TXWY P TO CROSS 'DID YOU SAY ACR Y XING RWY 25L?' HE SAID 'NO, I DON'T THINK SO!' AFTER XING, WE WERE TOLD BY GND TO CALL THE TWR UPON OUR ARR IN OAK. AFTER ARRIVING OAK, WE WERE INFORMED THAT WE CROSSED RWY 25L WITHOUT CLRNC. THE RESULTS OF THE INVESTIGATION ARE PENDING A REVIEW OF THE TAPES. CONTRIBUTING FACTORS TO THIS EVENT ARE: CONGESTED RADIO TFC, POOR VISIBILITY DUE TO RAIN AND DARKNESS, AND THE FO WAS ON HIS THIRD LEG OF IOE COMING FROM SO DC10. SUPPLEMENTAL INFO FROM ACN 564933: RECEIVED CLRNC TO CROSS RWY 25L, HOLD SHORT OF RWY 25R. READ BACK THE CLRNC AND TAXIED.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.